Hebei Huayang Steel Pipe Co., Ltd is one of the most experienced manufacturers and suppliers of dn 800 lsaw steel pipe for engineering in China. Welcome to buy discount dn 800 lsaw steel pipe for engineering made in China here from our factory. Quality products and low price are available.
Product introduction
Product Description
DN 800 LSAW Steel Pipe For Engineering is a high-performance longitudinal submerged arc welded steel pipe specially developed for large-scale engineering projects, including municipal infrastructure, industrial pipeline engineering, bridge construction, water conservancy projects, and offshore engineering. Manufactured in strict accordance with GB/T 3091-2015, GB/T 9711.1-2017, ISO 3183, and API 5L standards, it adopts high-quality Q235B/Q355B/Q390B carbon steel plates and advanced Longitudinal Submerged Arc Welding (LSAW) technology. With a nominal diameter (DN) of 800mm (corresponding to an outer diameter of 820mm), the pipe features excellent structural strength, high pressure-bearing capacity, stable weld quality, and strong adaptability to harsh engineering environments. It is perfectly suitable for long-term heavy-load, high-pressure, and complex working conditions in engineering projects, widely used in large-diameter water transmission and drainage, industrial process pipelines, bridge support, and underground comprehensive pipe gallery projects, providing reliable, durable, and cost-effective pipeline solutions for global engineering infrastructure construction.
Basic Product Specifications
Product Name: DN 800 LSAW Steel Pipe For Engineering
Executive Standard: GB/T 3091-2015, GB/T 9711.1-2017, ISO 3183, API 5L (Gr.B/X42), compatible with AWWA C200 (for municipal engineering projects)
Manufacturing Process: LSAW (Longitudinal Submerged Arc Welding), including JCOE/UOE/HME forming processes, steel plate cutting, edge milling, pre-bending, forming, internal and external submerged arc welding, weld annealing, hydrostatic testing, and finishing[3]
Steel Grade: Q235B, Q355B (core grades for general engineering), Q390B optional for high-strength engineering projects; API 5L Gr.B/X42 available for high-pressure engineering scenarios
Nominal Diameter (DN): 800mm (fixed, mainstream large-diameter specification for medium to large-scale engineering projects)
Outer Diameter (OD): 820mm (matching DN800, consistent with standard pipe size for engineering applications)
Wall Thickness (WT): 8mm – 16mm, custom thick-wall up to 20mm for heavy-load, high-pressure engineering projects (such as bridge support and offshore engineering)
Standard Length: 6m, 12m (standard), custom fixed lengths up to 18m available (matching large-scale engineering construction needs)
Delivery Condition: Annealed (standard, to eliminate weld residual stress and improve structural stability); stress-relieved treatment optional for high-precision engineering projects
Surface Finish: Black bare steel with anti-rust oil; hot-dipped galvanized (Zn coating ≥80μm), 3PE/FBE anti-corrosion coating (for underground, wet, or offshore engineering environments); epoxy resin coating optional for anti-corrosion and wear resistance
Pipe End: Plain ends (standard for flange connection); 30°/45° beveled ends for field welding; flange-connected ends optional for direct assembly in engineering sites
Application: Municipal comprehensive pipe gallery pipelines, industrial high-pressure process pipelines, bridge support and bearing pipelines, water conservancy project diversion pipelines, offshore engineering auxiliary pipelines, large-scale factory water supply and drainage pipelines, underground engineering ventilation and transmission pipelines
Grade & Process Explanation
Steel Grade Performance for Engineering: Q235B, Q355B, and Q390B are core carbon steel grades for engineering LSAW pipes, with excellent weldability, structural strength, and impact toughness, fully adapting to the heavy-load and complex working conditions of engineering projects. Q235B (minimum yield strength ≥235MPa) is suitable for conventional low-to-medium pressure, light-load engineering pipelines (such as general drainage and ventilation). Q355B (minimum yield strength ≥355MPa) offers higher strength and fatigue resistance, ideal for high-pressure, medium-load engineering scenarios (such as industrial process pipelines and water conservancy diversion). Q390B (minimum yield strength ≥390MPa) has superior high-temperature and low-temperature resistance, suitable for heavy-load, harsh environment engineering (such as bridge support and offshore engineering). All grades adopt low-sulfur (≤0.045%) and low-phosphorus (≤0.045%) composition, effectively resisting corrosion from engineering media and environmental factors, avoiding structural damage and service life reduction.
LSAW Process Advantages for Engineering Pipes: Adopting longitudinal submerged arc welding technology, with JCOE/UOE/HME forming processes, the steel plate is precision formed into a cylindrical shape and welded with internal and external double-sided submerged arc welding, ensuring uniform weld formation, dense weld seams, and high weld strength[3]. The post-weld annealing and stress-relieved treatment eliminate residual stress, ensuring the weld mechanical properties are consistent with the base metal, and enhancing the pipe's structural stability and fatigue resistance-critical for engineering pipelines to withstand long-term heavy loads and pressure. The LSAW process is suitable for large-diameter, thick-wall pipe production, which cannot be achieved by conventional ERW technology, perfectly matching the demand for large-diameter pipelines in large-scale engineering projects.
Engineering-Oriented Special Design: Optimized for engineering construction scenarios, focusing on structural strength, pressure-bearing capacity, and installation efficiency. The DN800 (OD820mm) specification is the mainstream large-diameter specification for medium to large-scale engineering projects, balancing transmission capacity, structural stability, and construction cost. Strict dimensional tolerance control ensures reliable connection with engineering fittings (flanges, valves, supports), facilitating on-site assembly and construction. Optional anti-corrosion coatings (hot-dipped galvanized, 3PE/FBE) adapt to underground, wet, offshore, and chemical-containing engineering environments, extending the service life of the pipeline to over 30 years, meeting the long-term service requirements of engineering projects.
Dimensional Tolerance (GB/T 3091 & GB/T 9711 Standard)
|
Item |
Tolerance (DN800, OD820mm) |
|
Outer Diameter (OD) |
±1.0% of nominal OD (820mm), max ±8.2mm |
|
Wall Thickness (WT) |
+12% / −10% of nominal WT, min allowable WT ≥ 85% of nominal WT |
|
Out-of-Roundness |
≤1.0% of outer diameter (≤8.2mm for OD820mm) |
|
Straightness |
≤2.0 mm per meter, ≤24 mm for 12 m length; ≤36 mm for 18 m length |
|
Length |
+200 mm / −0 mm, custom ±50 mm available for high-precision engineering projects |
Mechanical Properties (GB/T 3091 & API 5L Reference)
|
Property |
Q235B |
Q355B |
Q390B |
|
Minimum Yield Strength |
≥235 MPa |
≥355 MPa |
≥390 MPa |
|
Tensile Strength |
375–500 MPa |
470–630 MPa |
490–650 MPa |
|
Elongation |
≥26% |
≥21% |
≥20% |
|
Hydrostatic Test |
100% tested at 1.5× working pressure (minimum 3.0MPa), holding time ≥30 minutes, no leakage or permanent deformation |
||
|
Weld Tensile Test |
No weld separation, tensile strength ≥90% of base metal; weld toughness consistent with base metal |
||
|
Bend Test |
No cracks or weld defects after bending, complying with GB/T 3091 and API 5L requirements |
||
Note: For cold-region, high-altitude, or offshore engineering projects, the Charpy impact test (≥34J at -20℃) is optional to enhance low-temperature toughness and prevent pipe cracking in harsh environments; for heavy-load bridge support projects, additional fatigue test can be provided to ensure long-term structural stability.
Chemical Composition (Max. %, GB/T 3091 & API 5L)
|
Element |
C |
Mn |
P |
S |
Si |
|
Q235B |
≤0.20 |
≤1.40 |
≤0.045 |
≤0.045 |
≤0.35 |
|
Q355B |
≤0.24 |
≤1.60 |
≤0.040 |
≤0.040 |
≤0.55 |
|
Q390B |
≤0.22 |
≤1.70 |
≤0.040 |
≤0.040 |
≤0.55 |
Residual elements: Cu ≤0.30%, Ni ≤0.30%, Cr ≤0.30% (max. %). Strict control of impurities and non-metallic inclusions prevents rust, scaling, and structural defects inside and outside the pipe, ensuring the structural stability and service life of the pipe in engineering environments. The steel plate is subjected to strict surface derusting, cleaning, and edge milling before forming and welding, further improving weld quality and corrosion resistance, adapting to long-term immersion, buried, and heavy-load engineering conditions.
Manufacturing Process (LSAW for Engineering Pipes)
Raw Material Inspection: Select high-quality Q235B/Q355B/Q390B steel plates that comply with GB/T 3091 and API 5L standards, and strictly inspect the chemical composition, mechanical properties, and surface quality before production. The steel plates undergo derusting, oil removal, and cleaning to eliminate surface impurities, ensuring weld quality and structural stability of the pipe body.
Steel Plate Cutting & Edge Milling: Cut the steel plate into specified sizes according to engineering requirements, and mill the two edges of the steel plate by a precision edge milling machine to ensure the plate width, edge parallelism, and坡口 shape meet the forming and welding requirements, laying a foundation for high-quality welding.
Pre-Bending & Forming: Use a pre-bending machine to pre-bend the edges of the steel plate to the required curvature, then adopt JCOE/UOE/HME forming technology to gradually form the steel plate into a cylindrical shape through multiple steps of stamping or rolling, ensuring uniform wall thickness, high roundness, and consistent dimensional accuracy of the pipe body[3].
Internal & External Submerged Arc Welding: Adopt longitudinal submerged arc welding technology to perform continuous double-sided welding (internal and external) on the formed pipe blank. The weld seam is heated and melted uniformly under the protection of granular welding flux, forming a dense weld with no pores, cracks, or incomplete fusion. The welding process is controlled by an intelligent system to ensure uniform weld formation and stable quality.
Post-Weld Annealing & Stress Relief: Perform annealing treatment (600-650℃) on the welded pipe to eliminate weld residual stress, improve the toughness and structural stability of the pipe body, and avoid stress-induced cracking during engineering installation and use. For high-precision engineering projects, additional stress-relieved treatment is optional to further optimize the mechanical properties of the pipe.
Weld Inspection: 100% online ultrasonic testing (UT) and X-ray testing (RT) of weld seams to detect welding defects such as cracks, incomplete fusion, and porosity; visual inspection of weld surface to ensure smoothness and no burrs, avoiding affecting the connection and structural performance of the pipe.
Hydrostatic Test: 100% pressure test is carried out at ≥1.5 times the working pressure, with a holding time of 30-60 minutes according to GB/T 3091 standard, ensuring no leakage or permanent deformation-critical for the safety and reliability of engineering pipelines.
Anti-Corrosion Treatment (Optional): For underground, wet, offshore, or chemical-containing engineering environments, hot-dipped galvanizing, 3PE/FBE anti-corrosion coating, or epoxy resin coating is applied. The galvanized layer (≥80μm) effectively resists rust and corrosion, while the 3PE/FBE coating isolates soil, water, and chemical media, extending the pipeline service life.
Finishing: Cut the pipes to standard lengths, process pipe ends (plain or beveled), apply anti-rust oil to the surface, and carry out clear marking to complete the production process.
Product Advantages
Strict Standard Compliance: Fully manufactured in accordance with GB/T 3091, GB/T 9711, ISO 3183, and API 5L standards, meeting the acceptance requirements of municipal, industrial, bridge, and offshore engineering projects, suitable for global large-scale engineering infrastructure construction.
DN800 Large-Diameter Engineering Specification: Matches the mainstream large-diameter pipeline demand of medium to large-scale engineering projects, balancing transmission capacity, structural stability, and construction cost, widely used in municipal comprehensive pipe galleries, water conservancy diversion, and industrial high-pressure pipelines.
Superior Structural Strength & Pressure-Bearing Capacity: LSAW double-sided submerged arc welding + post-weld annealing, dense weld seams, high weld strength, and excellent mechanical properties, capable of withstanding heavy loads, high pressure, and complex engineering environments, avoiding structural damage and leakage.
Strong Adaptability to Engineering Environments: Low-sulfur low-phosphorus steel composition + optional professional anti-corrosion coatings, adapting to underground, wet, offshore, cold-region, and chemical-containing engineering environments, service life up to over 30 years.
Stable LSAW Weld Quality: Adopt JCOE/UOE/HME forming and double-sided submerged arc welding technology, uniform weld formation, low defect rate, weld mechanical properties consistent with the base metal, ensuring long-term structural stability in heavy-load engineering scenarios.
Suitable for Large-Scale Engineering Construction: Support custom length up to 18m, reducing the number of on-site joints, improving installation efficiency, and reducing construction cycle and cost; the pipe body is sturdy and durable, adapting to the harsh construction environment of engineering sites.
Cost-Effective & Reliable: LSAW process has stable production efficiency, suitable for large-batch production, low manufacturing cost; the pipe has long service life, low maintenance cost, and high cost performance for large-scale engineering projects.
Customizable for Engineering Scenarios: Accept custom wall thickness (up to 20mm), anti-corrosion coating type, pipe length, and pipe end form, adapting to different engineering conditions (heavy-load, high-pressure, cold-region, offshore).
Main Applications
Municipal comprehensive pipe gallery pipelines (DN800 mainstream large-diameter specification)
Industrial high-pressure process pipelines, factory water supply and drainage main pipes
Bridge support and bearing pipelines, high-altitude engineering auxiliary pipelines
Water conservancy project diversion and drainage pipelines, reservoir connecting pipelines
Offshore engineering auxiliary pipelines, coastal reclamation project pipelines
Underground engineering ventilation and transmission pipelines, tunnel engineering pipelines
Cold-region and high-altitude engineering pipelines (with low-temperature impact resistance)
Large-scale infrastructure construction pipelines (such as high-speed rail, airport supporting projects)
Quality Inspection & Certification
Dimensional Inspection: Full inspection of nominal diameter (DN800), outer diameter (820mm), wall thickness, length, straightness, and out-of-roundness to meet GB/T 3091 and API 5L standards, ensuring compatibility with engineering fittings and on-site installation requirements.
Mechanical Property Testing: Tensile test, bend test, weld tensile test, hydrostatic test, and optional Charpy impact test and fatigue test to verify product mechanical performance, structural stability, and pressure-bearing capacity, in line with engineering technical requirements.
Non-Destructive Testing (NDT): 100% Ultrasonic Testing (UT) and X-ray Testing (RT) for weld seams; magnetic particle testing (MT) for pipe ends to detect surface and internal defects, ensuring weld quality and structural safety.
Chemical Analysis: Heat analysis to confirm chemical composition meets GB/T 3091 and API 5L Q235B/Q355B/Q390B grade requirements, strict control of harmful elements and non-metallic inclusions, ensuring the structural stability and corrosion resistance of the pipe.
Certification: Mill Test Report (MTR) provided for each order, with full heat number traceability; third-party inspection (SGS, BV, CCS) available on request to meet global engineering project acceptance standards.
Packaging & Delivery
Packaging: DN800 (OD820mm) pipes are bundled with heavy-duty steel strips (8-12 strips per bundle), wrapped with waterproof and dust-proof woven cloth to prevent rust and damage during transportation and on-site storage; high-strength plastic end caps are installed to protect pipe ends and internal surfaces, avoiding dust and moisture contamination, ensuring the cleanliness and structural integrity of the pipe body.
Marking: Each pipe is clearly marked with GB/T 3091, LSAW, DN800 (OD820mm), steel grade, size (OD×WT), heat number, batch number, length, manufacturing date, and "Engineering Steel Pipe" identification, facilitating on-site identification and management, complying with the marking requirements of GB/T 3091 and API 5L.
Trade Terms: FOB, CIF, CFR, DAP, DDU all available, supporting various international trade cooperation methods for global large-scale engineering projects.
Shipping Ports: Major Chinese coastal ports (Tianjin, Qingdao, Shanghai, Ningbo), with professional loading equipment for DN800 large-diameter, thick-wall pipes, ensuring efficient and convenient global transportation, supporting timely delivery for engineering project schedules.
Customization: Accept customized wall thickness (8mm-20mm), anti-corrosion coating (hot-dipped galvanized/3PE/FBE/epoxy resin), lengths (matching engineering construction design), and pipe ends (plain/beveled/flanged) to meet specific engineering pipeline project requirements.
Contact Us
For quotation, stock availability, delivery lead time, and customized solutions of DN 800 LSAW Steel Pipe For Engineering, please contact our sales team. We have rich experience in supporting municipal, industrial, bridge, and offshore engineering projects, providing standard-compliant DN800 LSAW engineering steel pipes, and professional technical support for on-site installation, pressure testing, and anti-corrosion treatment, ensuring the safe, stable, and efficient operation of your engineering pipeline systems.
About us
Hebei Huayang Steel Pipe Co., Ltd. was founded in 2005, with a registered capital of 500 million yuan. The company covers an area of more than 1,000 mu, with annual sales of 10 billion yuan, more than 600 employees and an annual productivity of 2.75 million tons. The company has 17 new automatic steel pipe production lines and 14 high-frequency production lines, with a diameter of 73-660 mm; Three double-sided submerged arc welded steel pipe production lines with diameters of 406.4-1422.4mm;; 24 hot tube expanding production lines, with a diameter of 230-820mm; Two anticorrosion steel pipe production lines with a diameter of 73-1626 mm; 2 automatic painting production lines. With 3 branches and 5 offices, the products are sold to various cities and exported to more than 80 countries such as Southeast Asia, Middle East, Europe and America.
Packaging, transportation and delivery
Packaging, transportation and delivery
At Hebei Huayang Steel Pipe Co., Ltd., we apply standardized and reliable packaging solutions for all our steel pipe products. Our pipes can be securely packed by hexagonal bundling or circular bundling according to product diameter, wall thickness and customer requirements. Each pipe end is protected with high‑strength plastic pipe caps to avoid collision damage, dust and moisture during transportation and storage. The whole bundle is firmly wrapped with durable woven bags to enhance stability and prevent scratches or deformation.
We support a complete range of transportation methods to satisfy global customers, including road transportation, railway transportation, sea freight and container shipping. Based on our strategic location in Cangzhou, Hebei Province, we enjoy convenient access to major ports such as Tianjin Port, which greatly improves logistics efficiency and reduces transportation costs.
For standard specifications and normal order quantities, the general delivery time is about 30 days after order confirmation and deposit receipt. For large‑scale orders, special sizes or customized processing requirements, our production and sales team will formulate a detailed production plan and provide an accurate delivery schedule accordingly to ensure on‑time supply and stable performance for projects and clients worldwide.
Strict quality control
1. During and after the production, experienced quality inspectors randomly check the products to ensure that each steel pipe is qualified for production and application.
2. A nationally recognized laboratory with CNAS certification and certification by French Classification Society.
3. Have CNOOC access certificate, KOC oil company access network, ADNOC Abu Dhabi oil company access network, Petrobras access network, etc.
4. Accept the inspection by the third party designated/paid by the buyer, such as SGS and BV.
Certifications
API 2B
API 5L
GOST
ISO 9001
EN 10219
EN 10210
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